$ { \left[\begin{array}{rr}{1} & {3} \\ {1} & {-2}\end{array}\right]-\left[\begin{array}{rr}{1} & {2} \\ {1} & {4}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{1} & {3}-{2} \\ {1}-{1} & {-2}-{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{0} & {1} \\ {0} & {-6}\end{array}\right]}$